The present invention relates to a pump device for pumping a fluid, or particularly a pump device for pumping the fluid while the pumping device is immersed in the fluid.
In a pump as disclosed by JP-A-2001-503118 and JP-A-58-192997, a main shaft on which an impeller is mounted is supported by a hydrostatic bearing to which a fluid pressurized by the pump is supplied, and a thrust balance mechanism generates an axial force to be applied to the main shaft so that the axial force counteracts a thrust force of the main shaft.